Consider filtering out finalizer warnings in controller logs

[sbueringer]

Context:

• Since Kubernetes 1.29 (afaik) we are getting warnings when setting finalizers (see Our finalizers are not domain-qualified, and therefore do not conform to requirements #10914 for details).
• Since CR v0.19 it is possible to filter out warnings by setting a WarningHandler via rest.Config (⚠️ Remove options.WarningHandler controller-runtime#2903)

The warnings we get today in our controllers look like this:

{"ts":1724055396150.5093,"logger":"KubeAPIWarningLogger","caller":"log/warning_handler.go:65","msg":"metadata.finalizers: "addons.cluster.x-k8s.io": prefer a domain-qualified finalizer name to avoid accidental conflicts with other finalizer writers","v":0}

As we are aware of the "problem" and it will take us a while to migrate away from our current finalizers, I think we should consider to filter out the warnings in our controller logs.

Today logging the warnings produces a lot of spam and nobody that is running Cluster API can do anything about it.

[sbueringer]

/cc @dlipovetsky (just fyi)
/cc @chrischdi @fabriziopandini

[Karthik-K-N]

@sbueringer whats expected from this issue, If you can provide some info, I can try working on it.